Telephone-exchange system.



C. L. GOODRUM. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED 001.29. 1911.

1,262,323. 7 Patented Apr. 9,1918.

A/fly UNTTE STATES PATENT QFFICE.

CHARLES L. GOODRUM, OF NEW YORK, N. Y., ASSIGNOR T0 WESTERN ELECTRIC COM- PANY, INCORPORATED, OF NEW YORK, N. Y.,' A CORPQRATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

To all whom; it may concern:

Be it known that I, Cnanws L. GooDRUM, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Telephone- Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, and has to do more particularly with automatic line finders. The object of the invention is to provide effective and simplified means associated with the lines and switches for testing and extending the connections of calling lines to other means for handling different classes of service. s

In a central office where both manual and automatic service is given, there is a continual demand for a transfer of certain lines from one kind of service to the other. Such a change necessitates the use of difi'erent central ofiice equipment and a change in the subscribers telephone number.

It is a further object of this invention to afford a flexible means for meeting this demand and to do so without the addition of relays or other switching apparatus. It is still a fuither object of this invention to meet this demand without the necessity of a change in the subscribers telephone numher, it being necessary, so far asthe central ofiice is concerned, merely to make a minor change n the connections at the line relay of the changed line in order to transfer from manual service to automatic or vice versa.

In the preferred form of the invention, two kinds oflinel finders are used to serve a group of lines. The circuit arrangements in the two kinds of line finders are different and they will serve only the lines provided for their respective classes of service. The lines referredto are not arranged in subgroups according to their classes of service but appear indiscriminately in the line bank. The line finders are set in. motion by the closure of a line circuit of their particular class, and will stop on the terminals of lines of their class only.

The various features of the invention will be more fully understood upon reference to the following description taken in connection with the accompanying drawings, and

Specification of Letters Patent. Patented A r, 9, 1918 Application filed October 29, 1917. Serial No. 199,046.

' lines 5 and 6 and to multiply connected passive bank terminals a3, l 45 and 46, 47, 48.

The telephone lines are divided into groups of one hundred lines each. For each group of one hundred lines there is provided a plurality of line finders A andfB,

each having one hundred sets of line termi nals as 37, as, 39 and 4s, 44, 4.5 for line finder B, and 40, 41, t2 and 4:6, 4:7, 4:8 for line finder A.

These one hundred sets of contacts are further divided into sub-groups of ten sets of contacts each, so that in the operation of the switches A and B their brush sets 49, 50, 51 and 52, 53, 54 are first positioned corresponding to sub-groups containing the terminals of a calling line and subsequently operated to select the desired line in the subgroup. 1 I

In order to control the selection of the sub-group containing the terminals of a calling line, each line finder is provided with aset of group contact terminals as 55 and 56 shown, one for each sub-group of lines, also a rotatable brush 57 and 58 arranged to cooperate with the sub-group contacts.

Each sub-group of lines is provided with a resistance 59 and relay 33 for manual lines, and relays 30, 31 and 32 for automatic lines.

The switches used for line finders A and B are provided with ten brush sets consisting of three brushes each. Each set serves a sub-group of bank terminals. These brush sets are arranged spirally on a brush carrier (not shown) and are adapted to be rotated step by step'by the primary magnet PM, until one of the brush sets is positioned so that a vertical step-by-step movement by the secondary magnet SM will cause the brushes of the positioned set to successively the sub-group. In order to efiect a disconnect-ion o-i the briishesfrom the "terminals of brush sets to their normalposition responsive tothe energization of this magnet.

Line finder A is permanently associated with a well known manual switcllboardan rangement C, by means of which connectionsw'are established with other subscribers lines as L LineifinderB is permanently associated with an automatic selector arrangement D of a well known type, by

111691183 ofwhich connections are established with other subscribers? lines .asHl'f.

In order to more fully understand the operation of the illustrated arrangement, assume that a subscriber at substation L desires a connectionavith some other subscriber as substation L By removing his receiver from its switchhook a circuit is. closed to energize the line, relay LR from grounded battery, left-hand winding ofline relay LR, left-hand contact ofcut-ofii relayLGORf, line conductor 2, substation L line conductor l, right-hand cont-actor cut-oltrelay CUR, right-hand windingof line relay LR to ground.

The operation of relay LR closes a circuit from grounded battery, resistance59, armature and front contact of relay LR.,c011- ductor l, the winding of relay 33 to ground, thereby energizing relay A connection is also closed from battery, resistance 59, armature and second front contact of relay LR, and conductor 3 to contacts 37 andlO.

The resistance of relay 33 is s ufiiciently high to prcventthe operation of cutoff relay COR in series with it, and the-resistance of coil 59 is suiiiciently low to materially in' crease the potential of test terminals 37 and d0. 7

Referring now to the circuit of line finder A, the erlei ization of relay 33establishes a circuit for side-switchmagnet SSM from ground, armature and front contacto f relay 3-3, conductor '29, side-switch brush 21 and first position contact, group switch normal position contact and brush 57, left-hand armature and contact of relay 35, winding of side-switch magnet SSM to groundeebbattery. The energization of relay 33 also establishes a circuit for slow relay 3% from ground, armature and front contactof relay conductor 29, contact of'release magnet Rel, and the windingof relay 34:t0 grounded battery.

The operation of relay magnet SSM'closest-hestepping circuit of the primary magnetPM from ground, armatureandiiront contact of relay fi l, armature and c ontact of .sideswitch magnet SSM, armatureand contact of relay 35,

contact or primary magnet contact of secondary magnet SM, side-switch brush 22 and side-switch nacagas and first'position contact, Winding of. primarymag'n'et'PMvtoigronnded battery-.- The operation 0f the p-rimary-imagnetiBM interrupts its energizing circuit to rotate the brush sets and group switch step by step until the brush 57 of the group switch makes contact with a non-grounded group contact, when the energizing circuit of the sideswitch magnet SSML is broken, thereby opening the stepping-circuitof the, primary mgr-gnet, PM and allowing theside swi h to I top to position 2.

Cllhebrush set 52, 53, iozthe group contai1 1 ing the calling line-of substation L, and new. circui 1e$ the brush setsrvertically step by step until brush makcscontact withithe test termi- 119.1450 of a calling line, when a circuit is .closed to energize. relay 35, from; grounded battery, resistance 5.9, a mature and Contact of relay LR conductor 3., terminal 40,

is p s ione brush 52, conductor 10.,side-switchbrush 2O 7 and second position contact and the Winding of relay Soto ground. The operationvof relay 35 opensthe stepping. circuit of vthe secondary magnet SM and the holding circuit ointhesideswitch magnet SSM, both previously traced, thereby. stopping the movement'of the brush set 52, 53, 5% on the term-inals lO, 4:1, 42 of the calling line and allowing the side switclrto move to iposition3.

In side switch position 3, thecircuitof relay 35 previously traced is brokenand a circuit is closed to energizevthe cut ofi? relay COR, from-ground, third position contact.

and side-switch brush 20, conductor 10, brush 52, terminal 40, conductor 3 and the windingof cut-off relay CUR to grounded battery. 5

The operation of: the cut oii relay COR breaks the circuitof the linerelay LR previously traced; allowing it to release and thereby open the circuits through. resistance t0 terminals 37and a0 and t i 3 above traced.

In-side switch position 3 a signal circuit is closed at the-operatorflsswitchboardfrom grounded battery, left-hand wlnding-of relay 36, middle armature and contactof elay 60,

conductor 14, side-switch brusli Bland third position contact, conductor 8, brush 54, terconductor 9, side-switch brush 19 and third position contact, conductor 15, right-hand armature and contact of relay 60 and the right-hand winding of relay 36 to ground.

A new circuit is also completed to maintain the energization of relay 3 1, from ground, left-hand armature and contact of relay 36 conductor 28, side-switch brush 21 and third position contact, conductor 29, contact of release magnet Rel and the winding of relay 34: to grounded battery.

The connection is now completed by well known manual means.

It is obvious that the release of line finder A is now under the joint control of the operator and the subscriber at substation L. When thesubscriber at substation L has replaced his receiver to the switchhook and the operator, having received the disconnect signal thereby, withdraws her plug, the circuit for relay 34 is broken and a path is closed from ground, armature and back contact of relay 3 1, off-normal contact ON, the winding of release magnet Rel and grounded battery to energize the release magnet Rel and restore line finder A to normal, making it available for another call.

Assuming now that a subscriber at substation L desires a connection, by removing his receiver from the switchhook, he closes a circuit for line relay LE from grounded battery, left-hand winding of line relay LE left-hand armature and contact of cut-off relay COR line conductor 6, subscribers set L line conductor 5, right-hand armature and contact of cut-off relay'COR and the right-hand winding of line relay LR to ground.

The operation of line relay LE closes a circuit for the energization of relay 32 from grounded battery, left-hand winding of line relay LE left-hand armature and contact of cut-off relay COR armature and front contact of line relay LE conductor 61,1efthand armature and contact of relay 30, conductor 62 and the winding of-relay 32 to ground. Thereupon relay 32 locks up overthe circuit previously traced to conductor 61, the front contact and armature of relay 32 and the winding of relay 32 to ground.

Relays 30, 31 and 32 are common to the group of ten lines including line L Relay 32 closes at its right-hand armature and contact, a circuit from ground over con-V ductor ea to group switch contact 56, to designate the group containing the calling line L Relay 32 also closes a circuit through its right-hand armature and contact, from ground, conductor 64L, the winding of relay 31 to grounded battery, to operate relay 31 and start line finder B in search of line L Referring to the circuit of line finder B,

the operating circuit closed by'relay 31'is traceable as follows: from ground, righthand armature and contact ofrelay32, 'con ductor 64, right-hand armature and contact of relay 31, conductor 65, side-switch brush 26 and first position contact, conductor 66, right-hand armature and contact of release magnet Rel, armature and contact of the primary magnet PM, armature and contact of secondary magnet SM, side-switch brush 27 and first position contact, conductor 68 and the winding of primary magnet PM to grounded battery. Relay 31 also closes a circuit throughits left-hand armature and front contact from ground through the winding of relay 30 to battery to energize relay 30. i g

The operation of relay 30 opens at its right-hand armature and contact, a circuit to prevent the release'of the line finder B until after the finder switch has functioned.

The operation of primary magnet PM in terrupts its'energizing circuit, thereby moving the switch step by step in search of the group containing line L When the wiper 58 reaches group contact 56, which contact is grounded as traced above, a circuit is closed through brush 58, side-switch brush 25' and first position contact, winding of side-switch magnet SSM,conductor 68 and the Winding-of primary magnet PM to battery. V

Upon the energization of the side-switch magnet SSM, the side switch is stepped to position-2, where the operating circuit of this magnet is opened and a new holding circuit is established from ground previously traced in'the stepping-circuit to conductor 65, side-switchbrush 26 and second position contact, conductor 66, side-switch brush 25 and second. positioincontact, winding of side-switch'magnet SSM, conductor 68 and the winding of the primary magnet PM to *battery.

The closure of therright-han d contact of the side-switch magnet SSM completes a circuit for the secondary magnet SM from ground above traced in the stepping circuit to the right-hand contact of the release magnet Rel, conductor 69, conductor 67, ar-

mature and contact of the secondary magnet SM, side-switch brush 27 and secondpositheterminals of the lines in this group.-

When brush 49. is moved into contact with the test terminal 43 of acalling or non-busy line, a circuit isclosedto' energize the cutofl' relay of such line. This circuit is traceable trom grormdfaboxie traced in the step- --ping circuit to ZQQl'ldllCllOl 65,,s1de-sw1tch brush 26 and second position contact,

through resistance 70, armature and, front "contactof side-switch magnet SSM, conductor 13,:brush e9, terminal 43, conduct-or.

- 7 and the'winding of cut-off relay GB? to groundcdbat ry- Vhenthecuhefi relay (1013 is operated,

"thereby breaking the circuit of the line relay LE3, .thecircuit of group.- relay 32 is in turn roken by th en ning' o l z ne elay i onprimary magnet-PM andsecondary magnet SM, each above traced, thereby causing .the

switch to stop with brushes. 49, '50, 51 on line'terrninals 43, a l, 15- respectively, and mnring, by the release of the side-switch magnet; SSM, the side switch'to. position 3.

'ilhe release 0t relay 8.1 epensthe; circuit .oiE-relay and thereupon places the group circuit in condition receptive to a new call. [llhe release; 0t thev sideeswitch magnet SSM by. closing, its normal contact compl t s a circuit from ground, through the left-hand contact of the; release magnet Rel, to conductor'13, bruslr 1 19, terminal 43,. conductor 7 and therwinding of-the cut-01f relay OOR to battery, to; hold the-cut-off. relay operated.

In side switch position 3 the line connectionshare. extendedthrough conductor 16, side-switch brush 23:.andthirdi position contact, conductor 11, .brush- 51 terminal-45,

- line conductor 5, substation L line conductor 6, terminal 44, brush. 50, conductor 12, side-switchbrush 24: and third position contact: and conductor 17! -to-- a selector switch. a

V "lfhe completion of a connection to a subsmibers station L isaccomplished by: well known automatic means: through the agency of a sender in the calling subscribers' substati dn and automatic selector switches D.

"Theresist'ances or the cut-'ofirelays COR and @OBFareof thesamevalue. It'isto be oif relay of, the calling line through a re-- sistance of a specified value, and. the cutofi relay ofia; manualline L will not operate enceptrwhen dead ground is applied to ne of itspterminals- 3-7 or 40, that line find r B will}. not select a. manualline:

Whatis cl ed telephone system, a line bank,

inea said other line finder'foroperatingthecut ofi relays of the lines of the other of said classes, and means actuated by the opera tion of the cut-off relay ofa calling line of said other class for stopping said other line finder.

2. In a telephone system, a line bank,

manual and automatic lines terminating in said line bank, line finders arranged to cooperate with the terminals of said line bank,

and means associated with said line finders for differentiatlng, between sa1d manual and automatic lines in order to supply each with its respective class of service.

3. In a telephone system, the combination of a line terminating in a line bank, a line finder arranged to test all lines in said bank, a second line. terminating in said line bank, a second line finder arranged to test all lines in said line bank, means torrendering said firstline ineflectiveto said second line finder, and means for rendering said second line ineffective tosaid first line finder.

4. In a. telephone system, a plurality of line finders, a plurality of manual and of automatic link circuits, a plurality of manual and of automatic lines each multiply connected relative to each of said line finders, means for connecting said manual lines to said manual link circuits, and means for connecting said automatic lines to said automatic link'circuits.

5. In a. telephone system, a line multiply connected to fixed terminals in each of. a

pluralityv of line finders, a manually operable switch permanently associated with one of said line finders, means for actuating said line finder to" connect said line to said manuallyoperable switch, a second line multiply connected to fixed terminals in each of said plurality of line finders," a selectively operable'switch permanently associated with a second one of said linefinders, means for actuating said secondv line finder to connect said secondline with said selectively operable switch, means forrender-ing said first line finderv ineffective tosaid second line, and means for renderingsaid second line finder inefiective to said first line.

6. In a telephone system, a finderswitch multiple terminal bank, a plurality ofv subscribers lines of different .classesiappearing indiscriminately in terminals of said bank, finder switches of difierent classes arranged to traverse all the terminals of said bank but to serve only the class of lines to which each is allotted, means for starting the operation of any switch upon the initiation of a call by a line of the class to which such switches is allotted, and means for stopping any switch upon the terminals of only such a calling line as the class to which such 10 switch is allotted. v

In witness whereof, I hereunto subscribe my7name this 24th day of October, A. D. 191

CHARLES L. GOODRUM.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

Washington, D. C. p 

